You are here

Zoo Tales: Animal adaptations — physical, behavioral

Food, water and shelter. It’s what we all must have for basic survival in our environments. But many animals have had to go to extremes — had to adapt — to fill those basic needs.

These adaptations typically fall into three categories: Body parts, body coverings and behavior. Any or all of these adaptations, physical or behavioral, play a critical role in the survival of an animal.

Physical, anatomical adaptations are those such as skin coverings, claws, enlarged eyes, any type of structural modification made to a part of the body for a specific purpose. Behavioral adaptations are those changes in how an animal acts and can include such things as migrations, swarming and hibernation — usually in response to some type of external stimulus.

At the N.C. Zoo, visitors can daily see these adaptations in a variety of animals from rhinos to burrowing owls, ostriches to river otters.

Few animals illustrate these physical and behavioral adaptations better than giraffes. Their famously long necks allow them to browse leaves off tree tops, helping them avoid food competition from other grazers and providing a height advantage for spotting predators. A thick coating of glue-like saliva in their mouths protects them from injuries from sticks and thorns.

The giraffe’s enlarged heart muscles allow for more pressure to push blood to the brain, but at the same time, stretchable veins and valves in their neck prevent blood from rushing to the giraffe’s brain when it lowers its head to drink water, which would lead to loss of consciousness.

Another adaptation all-star at the zoo is the eagle. Along with most other birds of prey, eagles can see as much as eight times more clearly than the sharpest human eye can see. A golden eagle, for example, can see a hare from a mile away. Their adaptations are both physical and environmental — physical in the sense of strong gripping talons designed to carry prey, wings adapted to soaring and a beak that can both tear apart game and feed a young eaglet.

Environmentally, an eagle will remain in its territory all year if it has access to open water, but if the body of water freezes during the winter (making it almost impossible to get food), it migrates to the south or to the coast. Additionally, eagles pick migration routes that take advantage of thermal updrafts and food resources.

Few specific physical adaptations can match the elephant’s trunk, a flexible extension of its upper lip and nose containing more than 40,000 muscles and tendons. It’s used as fingers for eating and picking up objects, a siphon for drinking, a nose for smelling, a scoop for dust baths, a snorkel for breathing underwater, and, in some cases, even a defense weapon to fend off attackers.

An adult elephant’s trunk measures about seven feet and can weigh as much as 350 pounds — but contains no bones. Like a monkey’s tail, the trunk is prehensile and can be wrapped tightly around an object. At the tip of the trunk are two fleshy buds that act much like a human’s fingers [the Asian elephant has only one bud].

Although the river otter can hardly match the elephant in size and popularity, its physical adaptations are equally impressive and specialized. Because it often has to survive in extreme environments, the river otter had developed a metabolic heart rate that is fifty percent higher than similar mammals in warmer climates. This adaptation helps them maintain their body temperature in the worst of the cold water and weather they face regularly.

The otter’s coat is a combination of two different types of fur, an outer layer designed to protect the short, dense under-layer. In addition to helping them stay warm, this double-layer helps them float and shed water. Its nostrils are on top of its nose, making it possible to breathe while its body remains almost entirely under water. Other adaptations are highly sensitive whiskers that enable the otter to pick up vibrations in the water, aiding hunting under water and four webbed feet that help make it an excellent swimmer.

Animal adaptation is an on-going process. Over time, an animal’s environment may change little and the species might continue to fit its surroundings better and better. But on the other hand, environmental changes may occur relatively rapidly, with the species becoming less and less well-adapted, ultimately ending in species extinction.

* Zoo Tales, sponsored by the N.C. Zoo and written by Tom Gillespie, appears on Fridays. Send questions to Zoo Tales, 4401 Zoo Parkway, Asheboro, NC 27203. If your question is selected, you will receive two complimentary passes to the N.C. Zoo. The zoo is an agency of the N.C. Department of Environment and Natural Resources. For more information, call 1-800-488-0444.